It's easy to forget to turn off your amplifier after listening to music or watching a movie, which is why Instructable user zmashiah built an Arduino controller to power down his amp when it's not playing music, prolonging the life of his stereo while cutting down on power consumption.

The Arduino monitors the line level output of the amplifier and when it's quiet for longer than five minutes, it turns it off. He includes the all the codes you'll need to set this up yourself, but unless you happen to have the same Peachtree amplifier as him, you'll need to find your own IR codes. You can find the full guide over on Instructables if you're interested in making this for yourself.